In this article, we will discuss briefly about first syntax that
is Repair Table syntax.

REPAIR Table Syntax: It repairs corrupted mysql database
tables. A table gets corrupt due to several reasons like virus
attack, system failure, power failure, hardware problem, power
failure and so on. Corrupt mysql database tables can be repair by
this syntax.

MySQL database is a registered product of sun Microsystems. It is
platform independent in nature that means a database
administrator can install MySQL database on different operating
systems like windows, Linux, and others. MySQL database uses
tables for storing the data and records. Sometimes these tables
get corrupted by the several reasons like virus attach, software
malfunction, improper system shutdown, hardware problem, and so
on. When you are trying to repair corrupt mysql database by
“mysqlicheck” command but unable to fix then you can try lower
level of mysqlicheck command.

You can use lower level of mysqlicheck command in following
manner:

Stop Server Process: To use lower level command of
mysqlicheck, you should have to stop the server process. You can
do it by using service MySQL stop query.

Find Data Files: After end of the server process, you will
have to find the data …

MySQL organizes all the data as tables, irrespective of storage
engine used. If you are using MySQL with InnoDB tables, these
tables might get corrupt due to hardware faults, unexpected power
failure, MySQL code errors, kernel bugs and other similar
reasons. In such cases, InnoDB will typically give some errors
indicating table corruption. As a data restoration source, you
will need to use your latest database backup. But in case if
backup fails to restore required information or doesn’t exist,
you should scan your damaged database using third-party MySQL
Repair or MySQL Recovery tools.

You might encounter the similar error message while accessing an
InnoDB table:

MySQL is a reliable and higher secure relational database
management system that was developed to deal with much bigger
databases. Its improved performance, high speed and connectivity
make it a better client-server application that has a support for
different back-ends, client programs, and Application Programming
Interfaces (APIs). But one often faces corruption issues while
working with MySQL databases. The corruption may occur due to any
reason, such as quitting application in the middle of a write
operation, improper system shutdown, hardware issues etc. All
these reasons may prevent you from accessing your important
databases tables and other objects in the corrupt MySQL database.
To recover back all your inaccessible and valuable data in such
situations, you need to go for MySQL recovery through a reliable
third party utility.

MySQL is a relational database application, which is widely used
for many web based projects. Like any other database application,
MySQL also stores various important data. Hence, any problem with
the database, results in the complete inaccessibility of the
valuable data, which may lead to huge business loss. However,
there are many MySQL recovery software that can help you deal
with the MySQL problems and recover your precious data
back.

MySQL runs as a database server and provides multi-user access to
many different databases. For its usability and features, this
application is used by many big World Wide Web products, such as
Google, Wikipedia, Facebook etc. However, there are occasions,
when MySQL gets corrupted and all the data in it becomes
completely inaccessible.

There are thousands of such reasons behind possible MySQL
corruption. Below listed, are some of the most prominent
ones:

In order to start your MySQL server, you used to type the whole
path like: "C:\mysql\bin\mysql123" in your DOS prompt. However,
sometimes, the MySQL server fails to start with this usual
command and the reason may be any possible case of database
corruption or damage. In such a case, you cannot be able to
access your database and need any MySQL repair utility to repair
the troubled MySQL database and recover the data thereof.
In case of any corruption, you may encounter an error message at
the start of the MySQL server, which may be as below:

"Default storage engine is not available"

Moreover, in order to resolve the error, if you reinstall the
MySQL server without removing the data directory, the server
starts normally. However, to your utter dismay, while accessing
the any database table, you may encounter another error message
on the screen as below:

MySQL database has many commands to systematically maintain its
data. All of these commands have different syntax. Out of the
several commands, MySQL database has two most common commands
that are Optimize and Flush. The Optimize command of MySQL
database is used for the defragmenting the database files and use
the free space. The Flush command of MySQL database reloads and
clears all the internal patches used by database. You can use
Flush statement with RELOAD privilege. The above mentioned two
commands have different functionalities and features. Using MySQL
commands one after the another, your MySQL database table can get
corrupted. In such scenarios, your data saved in the table will
be inaccessible. For accessibility of table data, you should use
an advanced MySQL repair software to fix the problem.

Consider a practical scenario wherein, you run the Optimize
command and consequently run the Flush command, after doing this
you may …

MySQL is a popular database management system, a most widely used
for web databases, offers efficient techniques to ensure absolute
integrity of the database. When you start MySQLD (MySQL Server),
it automatically examines all the database tables for integrity.
MySQL Server also fixes the tables if they are marked as ´not
closed properly´ or ´crashed´. It backs up all the corrupted
database tables and makes their entries in the error log. Though,
it works in a number of cases, but cannot necessarily fix all the
corruption issues and fails to recover MySQL database.

The MySQLD technique cannot repair MySQL database if it is
severely damaged. As a practical scenario, where MySQL Server
cannot handle the table corruption, you may encounter the below
error message-

"Got an error from thread_id=1, mi_dynrec.c:368"

The above error message occurs when you start the MySQL server
for accessing the database …

In MySQL databases, the MyISAM table is the default database
engine, which provides a variety of functions to manage fields
and indexes. These tables are best used for table locking, which
makes it very useful while performing real-time transactions on
the websites. However, when these tables get corrupt due to any
random reason it makes the trading done on the web very insecure.
In such cases, you should try to repair MySQL table using some
appropriate methods. If none of the methods succeed, then I would
recommend you to use a third-party MySQL
Repair software to repair MySQL database.

Taking a practical case into consideration in which the following
error message is displayed while you are working on a MyISAM
table in the MySQL database:

"MySQL error code 145 = Table was marked as crashed and should be
repaired"

MyISAM is the default storage engine in MySQL server. It consists
of three types of files: .myi, .frm, and .myd. Of these three,
the MYI file is the index file that stores a counter in its
header. This header is used to signify whether a particular table
was closed properly or not. Sometimes, while using the myisamchk
command if you get an error message that means the table has
corrupted. Such problems can occur due to various reasons such as
power outages, abrupt system shutdown, mysqld process getting
killed in between a write operation, etc. You should use in-built
workarounds to repair the table. If you are not able to do this,
then you should use a third-party MySQL
repair software to recover MySQL database.

Consider a scenario wherein you have installed MySQL 5.0 in your
system. One day, when you try to run the myisamcheck command to
check a database table, it …

Content reproduced on this site is the property of the respective copyright holders.
It is not reviewed in advance by Oracle and does not necessarily represent the opinion
of Oracle or any other party.